Device for sealing the capsular bag of an eye and a method for delivering fluid or treatment substances to the lens of an eye

ABSTRACT

Disclosed are devices and methods for the transfer of fluids and potentially toxic chemicals into the lens capsule by creating a closed system preventing the fluids from entering the anterior chamber of the eye and thus causing damage to other ocular structures.  
     The invention comprises one or more fluid conduits which communicate with a plug which maybe inserted through the corneal incision and placed onto the anterior surface of the capsule around the capsulorhexis. The plug is adapted to seal against the anterior surface of the lens capsule.  
     In preferred embodiments, the flow of fluids into and out of the plug (and therefore the capsule) are controlled from a separate fluid flow controller.

TECHNICAL FIELD

[0001] The invention pertains to surgical devices and methods and moreparticularly to devices and methods for the prevention of posteriorcapsule opacification following cataract surgery.

BACKGROUND ART

[0002] During cataract surgery, the human lens is removed from withinthe lens capsule and replaced by an artificial lens. This is performedby opening a small hole in the anterior capsule (a capsulorhexis) andthen destroying and removing the human lens by phacoemulsification.However, lens cortex and epithelial cells remain following the lensremoval, and irrigation/aspiration is routinely used to remove thevisible cortex remnants. It is unreasonable to expect all lensepithelial cells (LECs) which are bound to both the anterior andposterior capsule to be removed by this method.

[0003] LECs which remain within the capsule have been shown to mutateand grow over the posterior surface of the implanted intra-ocular lens(IOL) thus causing posterior capsule opacification (PCO). Thiscomplication of cataract surgery has historically occurred at a rate ashigh as 30% however recent IOL designs have reduced this to around 2-5%at 2 years. It remains unclear what the longer term rates of PCO withthese IOLs will be.

[0004] The current treatment for PCO is a Posterior Capsulotomy using aYag laser. Although the complication associated with this procedure issmall, the cost is significant and there is a risk of retinaldetachment.

[0005] Current methods for reducing the rate of PCO include IOL design.It has been shown that a lens with sharp edges causes a barrier to LECgrowth. However, lens capsule fibrosis occurs and these IOLs have beenshown to cause vision problems particularly at night due to reflectionsfrom these edges.

[0006] It has been proposed that cytotoxic chemicals can be used todestroy these epithelial cells, however, there is a risk that thesechemicals damage other intranuclear structures.

[0007] Research is currently underway into using accommodating IOLs, andclear lens extraction for the correction of refractive errors. However,for these technologies to be successful chronically, the lens capsulemust remain flexible and free of fibrosis.

[0008] Therefore, there is still a need for a device which overcomes thecurrent problems associated with adequate capsule cleaning and LECremoval.

DISCLOSURE OF THE INVENTION

[0009] Accordingly, the invention provides devices and methods for thetransfer of fluids and potentially toxic chemicals into the lens capsuleby creating a closed system preventing the fluids from entering theanterior chamber of the eye and thus preventing damage to other ocularstructures.

[0010] The invention comprises one or more fluid conduits whichcommunicate with a plug which maybe inserted through the cornealincision and placed onto the anterior surface of the capsule around thecapsulorhexis. The plug is adapted to seal against the anterior surfaceof the lens capsule.

[0011] In preferred embodiments, the flow of fluids into and out of theplug (and therefore the capsule) are controlled from a separate fluidflow controller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIGS. 1 and 1(a) are schematic cross sections illustrating theplug and the lumens which carry fluids and vacuum,

[0013]FIG. 2 is a partially sectioned interior view of the plugillustrating an inclined, tangential fluid inlet,

[0014]FIGS. 3 and 3(a) are schematic cross sections illustrating amechanical engagement between a capsular plug and a capsule,

[0015]FIGS. 4 and 4(a) illustrate the use of an inflatable seal betweenthe capsule and the plug,

[0016]FIG. 5 is a schematic, cross-sectional, side view of an eyeshowing a first embodiment of a device according to the invention inuse;

[0017]FIG. 6 is a schematic, cross-sectional view of the device shown inFIG. 5,

[0018]FIG. 7 is a schematic, partial, cross-sectional end view of thedevice shown in FIG. 6,

[0019]FIG. 8 is a schematic side view of the device within a deliverytube before use,

[0020]FIG. 9 shows the device and delivery tube shown in FIG. 8 duringuse,

[0021]FIG. 10 shows the device and delivery tube shown in FIGS. 8 and 9after use,

[0022]FIG. 11 is a schematic, cross-sectional, side view of an eyeshowing a second embodiment of a device according to the invention inuse,

[0023]FIG. 12 is a schematic, cross-sectional, side view of the deviceshown in FIG. 1, and

[0024]FIG. 13 is a schematic, cross-sectional, end view of the deviceshown in FIG. 12.

BEST MODE AND OTHER EMBODIMENTS OF THE INVENTION

[0025] As shown in FIG. 1, a first embodiment of the invention comprisesa flexible plug 10 which can be inserted through the corneal incisionand placed onto the anterior surface 11 of the capsule 12 and around thecapsulorhexis 13.

[0026] The plug 10 is preferably attached to the anterior surface 11around the rhexis 13 by a vacuum seal 14. The vacuum seal 14 comprises acircumferential groove 15 which communicates with a lumen 16 whichcommunicates controlled vacuum pressure and extends through the cornealincision. In this example, the vacuum seal is generally circumferentialcomprising an inverted “v” shaped groove, defined in part by flexiblesealing lips 17. Fluid is introduced into and removed from the plug andcapsule by the second and third lumens 18, 19. The second lumen 18 isfor the aspiration of fluid and leads to an aspiration opening 20preferably formed at the highest interior point of the plug 10. Anaspiration lumen may have a larger internal diameter (ID) than anirrigation lumen.

[0027] As shown in FIG. 1(a), the aspiration port 20 can be covered by ascreen or castellation which prevents the aspiration port from sealingagainst the capsule and blocking the flow of fluid. A conduit whichextends from the lumen 18 to the opening 20 may be embedded within thewall 21 of the plug. In the alternative, the conduit 22 can extendthrough the wall 21 and to travel outside of the wall 21 as shown inFIG. 1(a).

[0028] The third lumen 19 carries the input or irrigation fluid and thislumen 19 also communicates with the interior 23 of the plug 10. It willbe understood that irrigation and aspiration may also be achievedthrough a single lumen, such as the second lumen 18. So long as theirrigation and aspiration steps are performed sequentially, the thirdlumen 19 maybe omitted.

[0029] In some embodiments, the aspiration port 20 and aspiration lumenID (about 0.3 mm) are larger in diameter than the irrigation inlet andtubing to allow equal flow into and out of the capsule.

[0030] In some embodiments, the device is moulded from a material suchas silicon or polyurethane such that the device can be rolled into aform allowing it to be passed through the normal cataract cornealincision to the anterior chamber of the eye. An insertion device maybeused for this purpose.

[0031] Other forms of the invention feature a stiff handle which isparallel with the infusion/aspiration lumens allowing the device to bepositioned onto the capsule. In one form of the invention, the handle isremovable. There may also be a web 24 extending tangentially from theedge of the device to meet the tubing and in the same plane as thetubing which is designed to guide the device through the incision onextraction.

[0032] As shown in FIG. 2, some embodiments of the invention provide anirrigation port 30 which opens through an interior wall 31 of the plug10. As shown in this FIG. 2, the irrigation port 30 enters the capsuleinterior 23 both tangentially and inclined toward the interior capsulesurface 11. This orientation provides a swirling motion to theirrigation fluid.

[0033] As shown in FIG. 3, the plug may take the form of an elongatedtube 40. The tube 40 terminates in a flange 41 which passes through therhexis. A mechanical seal with the capsule is made by lowering a secondclose fitting tube 42 over the first tube 40 and thereby gripping orclamping the capsule wall 21 between the second tube 42 and the flange41. This type of plug permits fluids to be introduced and removeddirectly through the central bore of the tube 40 or through separatelumens which pass through the tube 40.

[0034] As shown in FIG. 4, an elongated tube 50 and flange 51 maybesecured and sealed against the capsule by an inflatable seal. As shownin FIG. 4(a) the seal 52 comprises an inflatable ring which surroundsthe tube 50 above the flange 51. After the flange 51 is inserted throughthe rhexis and situated against the capsule wall, the seal 52 isinflated, lightly compressing the capsule between the seal 52 and theflange 51. Pneumatic pressure is introduced and withdrawn from the seal52 by a conduit or lumen 53 which may extend through the inside diameterof the tube 50, for example as shown in FIG. 4(a).

[0035] In some embodiments, it would be appreciated that with regard tothe example shown in FIG. 1, the vacuum pressure control to the vacuumseal 15 is precise. Accordingly, in these cases a controller is providedwhich has the capability to draw a vacuum, preferably at least 500 mmHg.The vacuum is measured by a pressure or flow sensor such that theinfusion of chemicals can be automatically halted if a vacuum leak isdetected. Therefore, the controller would accurately measure the vacuumpressure in the seal 15 and immediately halt the flow of irrigationfluid where a pressure drop is detected which could be possibly indicatethat chemicals could escape from the sealed capsule.

[0036] It will be understood that after the plug is sealed against thecapsule, a testing process may be employed which calls for a sequence ofthe fluids to be passed into the capsule by the controller, first theseal and strength of the capsule is tested using a neutral solution,followed by an active chemical chosen to destroy the LECs, and finallyby a solution to flush the active chemical from the capsule. In thealternative, the chemicals in the capsule can be neutralised before thesuction is removed and the device is extracted from the interior chamberof the eye.

[0037] In preferred embodiments, irrigation and aspiration through thelumens or otherwise, is controlled by pumps such as peristaltic orsyringe pumps. The fluid flow controller may be required to prime theinfusion and aspiration lines before commencing the procedure. It isimportant that the fluid flow is controlled such that the fluid volumein the capsule does not exceed the capsule volume.

[0038] In an alternate embodiment, the flow of liquid is derived fromthe pump or plunger position and confirmed by measuring the pressure onthe pump roller or plunger, or by measuring the liquid volume in theaspiration vessel.

[0039] Two methods of capsule flushing are envisaged. In the firstmethod, the capsule volume is kept constant by ensuring that theirrigation and aspiration flow rates are the same. In the second method,the capsule is first deflated, then inflated by infusing a known volumeof fluid or chemical less than or equal to the volume of the capsule.The cycle of inflation and deflation are repeated with a neutralsolution to flush the chemical from the capsule.

[0040]FIG. 5 shows another embodiment of a device according to theinvention, indicated generally by the reference numeral 110, for sealingthe capsular bag 111 of the lens 112 of a human eye 114 away from theremaining structures of the eye 114.

[0041] The eye 114 is generally composed of a conjunctival 116, acorneal 118, an anterior chamber 20, an iris 122, a posterior chamber124 and lens zonules 126.

[0042] Referring to FIG. 6, the device 110 includes a cover assembly 128and a stem 130. The cover assembly 128 has, in use, a substantiallyspherical-segment, hollow shape and is formed from an inner wall 132 andan outer wall 134 which have a passage 136 therebetween. The walls 132and 134 are maintained spaced apart to keep the passage 136 open by anarray of small spacer columns 138.

[0043] The cover assembly 128 is bounded by a peripheral rim 140 whichhas an annular opening in fluid communication with the passage 136. Therim 140 preferably has an external diameter of 5 to 7 mm. The coverassembly 128 also has an opening 142 in fluid communication with theinterior surface of the inner wall 132 and thus with the interior of thecover assembly 128. The stem 130 includes an inner channel 144 thatterminates at the opening 142 and an outer annular channel 146 in fluidcommunication with the passage 136 and thus the annular opening 140. Theinner channel 144 preferably has an internal diameter of about 1 mm. Theexternal diameter of the stem 130 is preferably about 3 mm.

[0044] Also shown in FIG. 7 are an inspiration tube or lumen 148 and anaspiration tube or lumen 150, which preferably have an internal diameterof about 0.2 to 0.3 mm. The purpose and function of the tubes or lumens148 and 150 will be described in more detail below.

[0045] As shown in FIG. 5, the cover assembly 128 of the device 110 is,in use, positioned by the surgeon against the lens 112 of the eye 114. Apreferred method for positioning the cover assembly will now bedescribed with reference to FIGS. 8 to 10.

[0046]FIG. 8 shows the cover assembly 128 and stem 130 contained withina delivery tube 152. In order to fit within the delivery tube 152, thecover assembly 128 is rolled into a substantially cylindricalconfiguration. When the device 110 is pushed out an open end of thetube, as indicated by arrows 154, the cover assembly 128 unfurls as aresult of its inherent resilience, as indicated by arrows 156, into asubstantially spherical segment configuration, as shown in FIG. 9. Thedevice 110 can then be operated in the manner shown in FIG. 5, whichwill be described in more detail below. After use, the cover assembly128 collapses whilst being pulled back into the delivery tube 152, asindicated by the arrows 158. The cover assembly 128 may include regionsof weakness, such as fold lines 160, to facilitate the collapsing. Asthe cover assembly 128 is contained within the delivery tube 152 beforeand after use it is able to be delivered into an anterior and posteriorchambers 120 and 124 of the eye 114 by passing the delivery tube 152through an incision (see FIG. 5) through the coat of the eye 114. Itwill be appreciated that the use of delivery tubes in positioningsurgical instruments in the interior of an eye through a small incisionis well known in the art.

[0047] The operation of the device 110 whilst in the position shown inFIG. 5 will now be described. The device 110 is positioned with thecover assembly 128 abutting the lens 112. This places the annularopening 140 against the surface of the lens 112. A vacuum of, forexample about 200 millimetres Hg, is then applied to the outer channel146 of the stem 130, for example with a manual, syringe-actuated pump.The vacuum communicates through the passage 136 and results in theannular opening 140 being suctioned to the surface of the lens 112 toform a substantially fluid tight seal therewith. The seal results in asubstantially closed cavity being formed between the interior or concavesurface of the inner wall 132 of the cover assembly 128 and the lens 112of the eye 114, thereby sealing the capsular bag 111 away from and theremaining structures of the eye.

[0048] The integrity of the seal can be tested by delivering a steriledyed fluid into the closed cavity through the inspiration tube 148. Thedyed fluid is removed via the aspiration tube 150.

[0049] Other fluids can then be delivered to the closed cavity throughthe inspiration tube 148. For example, if the capsular bag 111 of thelens 112 is opened with an incision, fluid can be used to flush outepithelial cells and lens fibres. The closed (sealed) cavity preventsthe fluids from reaching other areas of the eye. The inspiration andaspiration tubes 148 and 150 can then be used to flush the cavity andlens clean with saline or other suitable solutions.

[0050] The fluids are injected at a lower positive pressure than thevacuum pressure which forms the seal between the annular opening 140 andthe surface of the lens 112, so as to not interrupt the seal. This cancause the capsular bag 111 to enlarge. The fluids can be driven throughthe tubes 148 and 150 with, for example, a manual, syringe actuated,pump or a gravity fed infusion device.

[0051] The cover assembly 128 is preferably manufactured from a nontoxic, polymeric material, such as silicon, that is sufficientlyflexible to be rolled into the substantially cylindrical configurationand sufficiently rigid to maintain the spherical segment shape in thepresence of a positive pressure in the cavity.

[0052]FIG. 11 shows a second embodiment of a device according to theinvention, indicated generally by the reference numeral 200. Thereference numerals used in describing the eye 114 in relation to thefirst embodiment are again used to indicate like features with respectto the second embodiment.

[0053] Referring to FIGS. 12 and 13, the device 200 includes inner andouter concentric conduits 202 and 204 respectively. The conduits 202,204 respectively have an external diameter less then 2 mm and 3 mm andterminate in substantially flush angled ends 206 and 208. The peripheralgap between the ends of the inner and outer conduits 202, 204 defines arim 210 which functions in a similar manner to the rim 140 of the firstembodiment. The distal end of the interior of the inner conduit 202defines an opening 212 which functions in a similar manner to theopening 142 described in relation to the first embodiment. The gapbetween the conduits 202, 204 along their length defines a passage 214which functions in a similar manner to the passage 136 of the firstembodiment and is in fluid communication with the rim 210.

[0054] The operation of the device 200 is similar to that of the device110 of the first embodiment and will now be described. The device 200 ispositioned by a surgeon as shown in FIG. 1 by passing the distal end ofthe device 200 through a small (approximately 2.5 mm) incision throughthe coat of the eye 114. The device 200 is then positioned with itsdistal end abutting the lens 12. A vacuum is then applied to the passage214 which results in the opening 210 being suctioned to the surface ofthe lens 112 to form a substantially fluid tight seal therewith. Theseal again results in a substantially closed cavity being formed betweenthe interior of the inner conduit 202 and the lens 112 of the eye 114.

[0055] The integrity of the seal can be tested with dye, as wasdescribed in relation to the first embodiment. The inspiration andaspiration tubes 148 and 150 (see FIGS. 12 and 13) can then be used aswas described in relation to the first embodiment.

[0056] The device 210 is preferably manufactured from a non toxic,polymeric material that is sufficiently flexible to be manoeuvrable intothe eye and sufficiently rigid to maintain its elongated shape in thepresence of negative pressure in the 214 and positive pressure in theinterior of the inner conduit 202. The device 200 can be used with asmaller incision in the eye than the first embodiment and a smallerincision (preferably less than 2 mm or most preferably about 1.5 mm) canbe used to open the capsular bag 111.

[0057] As is evident from the above description, the advantage providedby the invention is that it allows the lens of the eye to be sealed fromother areas of the eye. As a result, fluids can be delivered to the lensof the eye, for example to irrigate the capsular bag to remove residuallens fibres and epithelial cells, without allowing those fluids tomigrate to other areas of the eye where they could harm cells requiredfor the eye to function correctly.

[0058] Although the invention has been described with reference to aspecific example, it will be appreciated by those skilled in the artthat the invention may be embodied in many other forms.

[0059] While the present invention has been disclosed with reference toparticular materials and details of construction, these will beappreciated to have been provided by way of example and not aslimitations to the scope or spirit of the invention as disclosed.

1. A device that seals an opening of a capsular bag of an eyecomprising: a. A plug b. A rim about the periphery of the plug c. Apassage in fluid communication with the rim wherein the rim is adaptedfor positioning adjacent to the lens of the eye such that applying avacuum to the passage substantially seals and affixes the rim relativeto the capsular bag of the lens and forms a substantially closed cavitybetween the interior portion of the device and the capsular bag of thelens.
 2. The device of claim 1, comprising a. a cover assembly which hasa flat or domed segment above a rim, the assembly having an externaldiameter smaller than the diameter of the lens and an internal diameterlarge enough to seal around an opening in the capsular bag. b. An innersurface residing with in the cover assembly, and defining a gap betweenthe inner surface and the cover assembly thereby defining the rim forsealing around an opening in the capsular bag; and c. A lumen extendingfrom the gap and terminating exterior to the eye whereby fluids orvacuum may be applied to the lumen.
 3. The device of claim 1 whereinthere are one or more additional lumens through the plug through which asubstantially fluid substance may pass through to the capsular bag. 4.The device of claim 3, where the one or more additional lumens enter aninterior surface of the plug.
 5. The device of claim 3 where there aretwo or more additional lumens through the plug for fluid irrigation andaspiration to the interior of the capsular bag.
 6. The device of claim 3where there are separate irrigation and aspiration lumens through theplug.
 7. The device of claim 3, wherein one or more lumens enter theplug interior tangentially and/or inclined toward the capsule surface toprovide a swirling motion to the irrigating fluid.
 8. The device ofclaim 6, where an ID of the aspiration lumen is larger than an ID of theirrigation lumen.
 9. The device of either of claims 3 or 6, where anaspiration lumen is located at a highest interior point.
 10. The deviceof claim 3, where an aspiration lumen port is covered by a screen orcastellation to prevent the capsule sealing the port and thus blockingfluid flow.
 11. The device of claim 1, wherein the device may be foldedor rolled or compressed without damage into a generally cylindrical orsemicircular form and is sufficiently flexible and resilient such thatit returns to its original shape when released.
 12. The device of claim1, being sufficiently resilient such that its shape is retained whenpositive or negative pressure of up to 760 mmHg is applied to one ormore passages.
 13. The device of claim 1, adapted to be rolled or foldedand then inserted using forceps or other surgical instruments into theinterior of the eye though a standard cataract corneal incision.
 14. Thedevice of claim 1, adapted to be rolled or folded and inserted into adelivery tube.
 15. The device of claim 1, adapted to be deformed to atapered or cylindrical configuration when pulled back into a deliverytube.
 16. The device of claim 15, further comprising regions of weaknesssuch as fold lines to facilitate collapsing.
 17. The device of claim 1further comprising a substantially rigid inner and outer conduits havingflush distal ends which are perpendicular to the surface of the capsularbag when angled though the cornea.
 18. The device of claim 3 whichfurther comprises an additional controller which provides a specifiedvacuum to the rim.
 19. The device of claim 18 whereby irrigation ishalted when a pressure sensor and/or flow meter detects a vacuum leak.20. The device of claim 18 where irrigation and aspiration arecontrolled by pumps such as a peristaltic or a syringe pumps such thatthe fluid volume in the capsule does not exceed the capsule volume. 21.The device of claim 1 wherein the fixation to the capsular bag is by aninflatable seal.
 22. The device of claim 1 wherein the fixation is bybiocompatible adhesive such as fibrin glue.
 23. The device of claim 1,further comprising a generally rigid manipulation handle which my beeither integral to the device or removable.
 24. A method wherebytreatment fluids are passed into the capsular bag of the eye, which hasbeen substantially sealed from remainder of the internal eye by thedevice of claim
 1. 25. The method of claim 24 whereby a testing processis employed by irrigating with a neutral fluid to test the seal of thedevice of claim 1 prior to using an active chemical.
 26. The method ofclaim 24 whereby an active chemical is used with the device of claim 1to destroy lens epithelial cells.
 27. The method of claim 24 whereby anneutralising chemical is passed through the device of claim 1 toneutralise the active chemical
 28. The method of claim 24 wherebyirrigation and aspiration proceeds with controlled irrigation and/orvacuum pressure.
 29. The method of claim 24 whereby irrigation andaspiration proceeds with controlled irrigation and/or vacuum fluid flow.30. The method of claim 24 whereby the volume of the capsule is keptconstant.
 31. The method of claim 24 whereby the capsule is repeatedlyinflated and deflated though the repeated irrigation and aspiration of aset fluid volume.
 32. A plug for sealing against a capsular bag andproviding fluid communication with an interior of the bag, comprising:an inner tube which terminates in a flange; the flange adapted to passthrough a rhexis; a second close fitting tube; the second tube adaptedto slide over the first tube so as to clamp the capsular bag between thesecond tube and the flange.
 33. The plug of claim 32, wherein: the innertube has a central bore into which one or more lumens may pass directlyinto the capsular bag.
 34. A plug for sealing against a capsular bag andproviding fluid communication with an interior of the bag, comprising: atube terminating in a flange; the flange adapted to pass through arhexis; an inflatable seal located above the flange; a conduit leadingfrom the seal to a means for inflating the seal so as to clamp thecapsular bag between the seal and the flange.
 35. A plug for sealingagainst a capsular bag and providing fluid communication with aninterior of the bag, comprising: concentric inner and outer tubes; thetubes having angled and flush ends; a gap at the ends defining a rim; aninternal diameter of the inner tube providing access to the interior ofthe capsular bag.
 36. The plug of any one of claims 32 to 35, furthercomprising: one or more lumens passing through the plug, which lumen maycarry fluid into or out of the capsular bag.
 37. The plug of claim 36,wherein: there are separate irrigation and aspiration lumens.
 38. Theplug of claim 36, wherein: an ID of an aspiration lumen is larger thanan ID of an irrigation lumen.